This invention relates to beverage cans and is particularly directed to a closure construction for such cans of the type which may be opened by lifting a tab member to partially sever a sealing tab from the can top.
It has previously been proposed to provide metal beverage cans formed of aluminum, light gage steel, or the like, having a top with a key or pear-shaped opening defined by a score line or line of weakening. A pull tab is connected to this panel portion in such a manner that when the pull tab is lifted, the sealing panel is partially severed along the score line and is forced downwardly into the interior of the can. Such prior art cans are advantageous in that they can be opened in a simple manner without the use of auxiliary implements.
Cans of the type described are further advantageous in that the panel portion which is torn to expose the pouring opening is not completely separated from the can, but remains attached to the main can body so that the problem of excessive littering by torn tear strips, lifting tabs or the like is eliminated.
Despite these advantages, however, cans of the type described are subject to one or more serious disadvantages. In the first place, such cans are inherently unsanitary since the unprotected top is forced downwardly into the contents of the can as a normal incident to can opening. This may result in contamination of the beverage or other contents of the can.
A second disadvantage of prior art cans is that the pull tab and panel are frequently joined by a rivet-like construction involving the formation of a hollow rivet on the panel which passes through an opening in the pull tab and is subsequently flattened to hold the two members in assembled relationship. This so-called rivet construction is a frequent cause of rejects due to leakage as a result of the formation of cracks in the rivets during assembly of the closures.
A still further objection of other can closures which have been proposed is that they are difficult to open, i.e., they require an inordinate amount of force to operate the pull tab or the like.